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Richard Vida released Critter 1.4, including a version for Android. This ARM binary imports well into Chess for Android. A quick 1-second-per-move tournament from both sides of all opening lines in the Nunn test suite on a Nexus S ended in favor of the previous version though.

Lucas Braesch released DoubleCheck 2.3 and I put an ARM binary on UCI and XBoard engines for Android (you can find another binary for ARM on Jim Ablett's website). Below, I show the results of a quick one-second-per-move tournament played from both sides of all lines in the Noomen test suite 2012 between some recent versions (32MB hash size, Nexus S).

Another engine for ARM-based Android devices! Tony Hecker kindly made ARM binaries of Tjchess available as either an UCI engine or a XBoard engine. Both import well in Chess for Android. Some screenshots below. With so many new engines, is it time for yet another Android chess engine tournament?

Jim Ablett kindly compiled Jon Dart's Arasan engine for ARM-based Android devices so that it can be imported in Chess for Android. The engine supports multithreading, Nalimov endgame tablebases, and clocked at about 100Kns out of the opening on my Nexus S.

As posted earlier, Jim Ablett posted an Android Chess Engine Bundle, which various UCI and Win/XBoard engines that can be imported in Chess for Android. Because the Win/XBoard protocol feature is still relatively new in Chess for Android and conducted a test tournament between all the XBoard engines (except gfc-08-rev5-ja which often claims a mate without actually making the move; I am not sure if the standard allows this, but it seems weird that the GUI should verify the claim).

During this tournament I found a few opportunities for improving the GUI's handling of the protocol, which will be released soon. Also, the next release will add the much requested pondering feature (also called permanent brain).

Group B has finished a complete thirty seconds-per-move tournament in Chess for Android, played from both sides of all positions in the Nunn opening suite under the conditions described earlier. Regrettably I found that Crafty was put at a slight disadvantage (not something that would have changed the outcome though) due to a misinterpretation of XBoard's resign plus move command, causing a resign by illegal move in the next game. This issue has been fixed now.

After many more cycles on my Nexus One, Group D has just finished a complete thirty seconds-per-move tournament in Chess for Android, played from both sides of all positions in the Nunn opening suite under the conditions described earlier. Quite a shuffle-up in the results this time compared to the qualification tournament.

Congratulations to Aaron Becker for Daydreamer's promotion to Group C.

The Micro-KIM arrived today! I did some initial experimentation with my 6502 cross-assembler and was happy that the paper tape format l recently added could be uploaded to the device without any problems. What better first program to write than "HELLO WORLD" (except only HELLO fits on the display)? It was fun figuring out how to control the display using low level 6502 programming.

After burning cycles on my Nexus One for many days, Group E has just finished a complete thirty seconds-per-move tournament, played from both sides of all positions in the Nunn opening suite under the conditions described earlier.

Congratulations to Ben-Hur Carlos Vieira Langoni Jr for RedQueen's promotion to Group D.

As a present, my wife ordered the Micro-KIM from Briel Computers for me, which is a modern replica of the KIM-1 microcomputer. Even though I learned machine code on the 6510 of the Commodore 64, I remember seeing the KIM-1 in an electronics store much earlier, and I was intrigued right away. I can't wait for it to arrive to do some vintage programming.

In anticipation of the Micro-KIM's arrival, I extended my 65xx cross-assembler (available for Windows, Linux and MacOS) with the paper tape format, either in the original binary format (option -p) or in a text representation (option -P) so that its output can feed directly into the Kim's terminal interface. I simply generated the format based on old documentation and it is still untested. If someone is interested in trying it out, I would appreciate early feedback. Otherwise, I will report back when I get my Micro-KIM.

For example, using the assembler on this little test assembly program:

Charles Bond wrote a nifty 6502 simulator, called Soft6502, which I find useful for testing small programs written for the 65xx microprocessor family. The simulator supports the full 6502 instruction set and two 8-bit ports for input and output.

Programs can be entered one byte at the time through the keyboard or, more conveniently, loaded from file. The simulator uses the H6X file format, which is a simple, but surprisingly versatile way of representing 6502 code (essentially an ASCII representation of addresses followed by bytes). I have extended my 65xx cross-assembler (available for Windows, Linux, and MacOS) to support this H6X file format, so that its output can be directly fed into Soft6502.

I just released version 3.0.2 of Chess for Android, available at the Android market and as direct download. This release enhances XBoard/WinBoard support (infinite analysis, resign feature, older idioms used by various engines).

I completed a qualification tournament from both sides of the first Nunn position at one-second per move on a Nexus One (1GHz Snapdragon). Where applicable, UCI engines were given an 8MB hash table and 1MB endgame tablebases cache (the complete 3- and 4-piece Nalimov, Gaviota, Scorpio, and Robbobases endgame tablebases reside on SD card). XBoard engines play at their default settings. Since the Nexus One is a single-core device, "pondering" was disabled

The qualification results are used to split the engines into separate groups. Engines in each group will play each other at longer time controls, starting with the lowest group. The number one in each group will promote to the next group.

I made various improvements in the WinBoard/XBoard implemention in Chess for Android and are now able to successfully import and play with the following XBoard engines (I also tested the corrected UCI sungorus engine).

I ran tournaments between different versions of the same engine to determine which one would be their representative. Below I show the results of a fast round-robin tournaments using Chess for Android on a Nexus One, Nexus S, and Galaxy Tab with, where applicable, 8MB hash table and 1MB tablebases cache (Nalimov, Gaviota, Scorpio, and Robbobases reside on SD card). Each version played each other version from both sides of the Nunn opening suite. The number one engine will play in the longer time control tournament (which is not always the latest version; engine authors let me know if you prefer otherwise since some results were pretty close). Also, Pablo Vazquez and Jim Ablett kindly worked together to fix the issue in the sungorus. It now runs correctly and will participate in the tournament.

The list of UCI and XBoard engines for Android is getting longer, and I am pondering about a more serious tournament at longer time controls in Chess for Android. As a first step, I tested all available Android binaries. The list is shown below. An "X" indicates that the engine has trouble running in Chess for Android (if you are the engine author and are interested in fixing this, please contact me for details).

Next, I probably do a few quick tournaments to divide the engine in groups by strength, followed by tournaments at longer time control. Please feel free to contact me if you are interested in participating, if you don't know how to compile your engine for Android (ARM), or if you have good ideas about the format of this tournament. I am not really an experienced tournament manager, but merely do this for fun to get an idea of the relative strength of these engines.

Version 3.0.1 of Chess for Android is available at the Android market and as direct download. It introduces the first, albeit simple support for the Chess Engine Communication Protocol (XBoard/WinBoard). Many features that are already supported for UCI (e.g. options setup, infinite analysis) as well as some XBoard specific features (e.g. resign) are still missing for this first version. I hope to add these features soon. Nevertheless, it is already possible to run tournaments between engines.

Chess for Android now contains sufficient functionality to perform the first inter-protocol tournament between the built-in Java engine, the UCI engine BikJump, and the WinBoard/XBoard engine Fairy-Max. Ten random opening book games between these engines at one second per move on a Nexus S ran without problems to completion with the following results.

I am exploring extending Chess for Android with some rudimentary support for the Chess Engine Communication Protocol (often simply called the XBoard or WinBoard protocol), which will enable importing not just UCI but also XBoard/WinBoard engines.

A very first prototype is functioning. I made an Android binary of the engine FairyMax (written by H.G. Muller, who was also very helpful providing more background), and imported this in Chess for Android. Some screenshots are shown below.

I still have to deal with a lot of details, but it will be fun to support both protocols, and even run tournaments between UCI and XBoard/WinBoard engines.

Miguel A. Ballicora released Gaviota v0.84. I tested the Android version against an earlier release with a quick one-second-per-move tournament on a Nexus S, setting the hash size to 32MB and using the Silver Opening Suite and some Gaviota tablebases on SD (the latest release fixes an issue with tablebase setup on Android). Below are the results. The new version seems much stronger!

Michel van den Bergh posted a new release of GNU Chess (5 branch). To test the Android binary, I ran a one-second-per-move, 32MB hash tournament on a Nexus S, using the Silver Opening Suite, with Gaviota tablebases on SD. Below are the results. Although the latest release was mainly for FRC support, it also seems slightly stronger.

Running tournaments on diverse test suites gave me more confidence in the correctness of my FEN and PGN parser. This time Chess for Android found bugs in the "Rebel ELO Test". Positions ELO 30, 121, 170 do not set the castling rights for either black or white properly, even though castling is the first given move (that is, the move the engine is supposed to find when used as a tactical test suite; when used as an opening suite, this move is obviously played right away).

The results of (mis)using the corrected test suite as an opening suite in a fast match between the built-in Java engine and Stockfish 2.1 on a Nexus One is shown below.

Here is one of the sparse victories of Chess for Android playing white from a very advantageous position. Nevertheless, I am happy that it found the right continuation as 1. Qc8+ (given in the suite) Kg7 2. Qf8+ Kg6 3. Qf7+ K…

I ran various tournaments using the "Max Euwe suite", from the hand of the famous grandmaster who inspired many Dutch aspirant chess players, including myself. During the first tournament, Chess for Android detected bugs in positions 146 and 148, where the castling rights are not set properly for white, even though white actually castles in the first given move (that is, the move the engine is supposed to find when used as a tactical test suite).

For example, in position 146, the embedded FEN string in the PGN file:

As a fun way to test the new opening suite feature, I conducted a fast match between the very strong Komodo 3.0 chess engine and the built-in Java engine of Chess for Android using the "beat the masters suite" (a version with 251 test positions). Komodo is clearly much too strong for my own humble engine and the suite was meant to test the quality of moves found by chess engines, not as an opening suite. Nevertheless, since some positions give one side a very strong advantage, it seemed like a fun way to test the new opening suite feature.

The outcome was as expected: Komodo won most games and only a few draws occurred. However, Chess for Android had one victory.

1 Komodo32 3 AB +491/ -1/=10 98.80% 496.0/502 2 Chess for Android +1/-491/=10 1.20% 6.0/502 In the position below, with black to move and only half a second thinking time per move, Komodo played 1... Rxe2, which yields a lost position (black should have played 1...hxg6).

Chess for Android v3.0 is available from the Android market or as direct download. New features include:The possibility to play engine tournaments from both sides of any external book in PGN format, as explained in this blog posting.Layout and formatting improvements in the UCI analysis output window. Light grey board color.Relaxed FEN parsing to accept non-standard, but frequently occurring omissions in the FEN string.Ability to view simple cross-table while tournament is in progress (>> button).

Using the new upcoming opening suite feature in Chess for Android, I conducted a tournament between the most recent Android versions of Stockfish, Komodo, and Critter (32MB cache, 1s./move) from both sides of the "Silver Opening Suite" (300 games total). A screenshot of the tournament in progress is shown below (also note that the upcoming version improved the layout and display of the engine analysis window).

To eliminate the effect of opening books, it is a common practice to test the strength of chess engines by letting them play from both sides of a pre-selected set of opening positions. Earlier versions of Chess for Android already supported the option to play engine tournaments from both sides of 50 positions of the built-in book (yielding 100 games total between each engine pair). The upcoming 3.0 release will add the option to play both sides of any external book in PGN format, such as the famous "Nunn Positions" (published by GM John Nunn) or the "Silver Opening Suite" (published by Albert Silver).

To use this feature, long press the notation window, and select "UCI Engine Support", followed by "Engine Tournament". Then select the "all games from both sides of external book".

This will open a file navigation window, starting at the root of the SD card. Navigate into the directory and file of the desired opening suite. This will promp…

Don Dailey and Larry Kaufman's Komodo version 3 is now available for Android (ARMv5TE) at UCI engines for Android. A quick one second per move tournament ended in favor of the previous version 2.03 (possibly because Don fixed the movetime command to honor the given time exactly; previous versions would sometimes use more time, which may have skewed estimates of their strength a bit).

I just released version 2.9.4 for Chess for Android, available from the Android market or as direct download. This version introduces the much requested "infinite analysis" mode for an imported UCI engine, in which the engine reports its analysis of positions without actually making moves. To enable this mode, change the level to free play, as shown in the following screenshots.

If an UCI engine is imported, its analysis of the current position will appear below the board. The user can freely play through previous games or make new moves. When at the end of a game still in progress, pressing the ">" button will play the best move found by the UCI engine. Changing the level, or unloading the UCI engine will exit the "infinite analysis" mode.

Although the feature may seem simple, it was actually far from straightforward to implement, also because not all UCI engines behave the same for the "go infinite" command. Please let me know if you encoun…

I compiled Lucas Braesch's DoubleCheck 1.1 for Android (ARM) and put it on the UCI Engines for Android website. The engine works reasonably well in Chess for Android. However, because the UCI command movetime is not implemented yet, it plays almost instantaneously, making matches to determine its strength less useful at the moment.

Jim Ablett kindly ported Gary Linscott's engine GarboChess 3 to various platforms, including Android. I also made a dynamically linked binary available at the UCI engines for Android website. As can be seen in the screenshot below, the UCI engines does not provide many options, but it plays strong.

Below the results of several quick matches on a Nexus S using random book opening play, one second-per-move, 32MB hash, and 8MB tablebases cache with the 3- and 4-piece Nalimov, Gaviota, Scorpio, Robbobases endgames on SD card.

To test recently released versions of Android engines, I conducted a new tournament between the top UCI engines on a Nexus One using a random book opening play, one second-per-move, 32MB hash, and 8MB tablebases cache with the 3- and 4-piece Robbobases endgames on SD card. Congrats again to the Stockfish team!

Richard Vida released Critter 1.2 for various platforms, including ARM-based Android devices. Below you can see some screenshots of this UCI engine running in Chess for Android.

To get a rough idea of the strength of this new engine, I conducted a few quick matches with other engines on a Nexus One using a random book opening play, one second-per-move, 32MB hash, and 8MB tablebases cache with the 3- and 4-piece Nalimov, Gaviota, Scorpio, Robbobases endgames on SD card. More games upcoming.

Don Dailey and Larry Kaufman released version 2 of their chess engine Komodo. You can find an ARM-based Android binary on UCI engines for Android. The new release seems stronger than the already impressive previous version. A quick one second-per-move, 32MB hash tournament on a Nexus S against Komodo1.3 resulted in 73 vs. 27 in favor of Komodo2.

After this previous tournament, I conducted a tournament between various versions of the top engines under the same settings with more games. The results are shown below. Congrats to the stockfish team for winning this tournament!

I computed the perft number for 8x8 checkers for depth 24 with the same distributed implementation I used earlier for depths up to 23. Below you see the perft breakdown per move (called "divide") from the initial position for depths 22, 23, and 24.